The Infected (Zombies): Origin: The specific origin is initially unknown (viral, fungal, experimental bio-weapon leak?), adding an element of mystery that might be uncovered later. Transmission: Primarily through bites or deep scratches transferring infected bodily fluids (blood, saliva). Airborne transmission is not a factor, making contained spaces potentially safer if unbreached. Characteristics: These aren't slow, shuffling Romero-style zombies. They are relatively fast movers, capable of bursts of speed, particularly when alerted to prey ('Rage' virus style, but maybe not quite 28 Days Later fast). They are driven by relentless, primal aggression towards the uninfected. Senses: Primarily drawn to sound and movement. Their eyesight is moderate, perhaps degrading over time or worse in bright light. They might have a crude sense of smell for living flesh at close range. Weaknesses: The classic "destroy the brain" rule applies. Severe head trauma is the only reliable way to neutralise them permanently. They are relentless but lack intelligence or problem-solving skills, often hampered by obstacles or predictable patterns. They might also be sensitive to certain stimuli (extreme noise overload, specific frequencies - potential plot points). They don't "tire" but can be damaged and slowed by bodily harm. Turning: The incubation period is relatively swift – anywhere from minutes to a few hours after exposure, depending on the severity and location of the bite/scratch. This creates immediate tension after any close encounter. Societal Collapse :Speed & Nature: The initial outbreak spreads rapidly through major population centres, amplified by modern travel. Crucially, the societal collapse happens almost as fast, not just due to panic, but because fragile, interconnected systems shatter under the strain. Communications overload and die. Power grids fail due to lack of personnel and targeted damage (intentional or accidental). Supply chains (food, fuel, medicine) break within days. Systemic Failure: Law enforcement and military are initially overwhelmed, fragmented, and suffer heavy casualties. Conflicting orders, desertion, and the sheer scale of the crisis lead to a rapid breakdown of organised response. Pockets of authority might remain, but they are often isolated, ineffective, or turn tyrannical (martial law zones that become traps). Human Factor: Fear and desperation turn survivors against each other almost immediately. Widespread looting, the formation of violent gangs, armed survivalist groups claiming territory, and the collapse of trust become as dangerous, if not more so, than the zombies themselves. Safe zones are rare, often temporary, and frequently fall due to internal strife or resource depletion as much as zombie hordes. Information is unreliable, rumours spread like wildfire, and paranoia is rampant.